Thanks Richard, I'm going to base mine loosely on MT Lorraine, an Aussie tug based in Queensland.
Survey (QLD) USL 2B (4 persons), USL 2D (6 persons)
Length 15.3 metres
Beam 4.7 metres
Draft 2.0 metres
Displacement 47.8 tonnes
Bollard Pull 7 tonnes
Fuel Cargo Capacity 20,500 litres
Water Cargo Capacity 2,000 litres
Machinery & Equipment
Main Engines 2 x 300 hp Cummins NT855
Generator 1 x 12 kva Nissan
now it's calculator time to figure the scale, just on 1/48th so "O" Gauge figures will be close enough.
The only other pic I've found is from the bridge to rear over the stern.